[R] Simple NLME problem (I hope)

[Vumani Dlamini]

Dear R-Users:

I would like to fit a multilevel model using LME such that the parameters 
after fitting the multilevel in two separate groups and when I use the 
complete data (with interactions between the grouping variable and the other 
variables) set are comparable (or the same).

The problem I am having currently is that I am not sure whether it is 
possible to let the random error term to vary by group such that the models 
are comparable. At present only one random error term is estimate and this 
"sort of" distorts the parameter estimates for the fixed and other random 
effects.

Looking forward to your help.



Vumani Dlamini